HANCOCK COUNTY — Lilly Madden couldn’t wait to get her driver’s license shortly after she turned 4 on Feb. 29.

The sophomore at New Palestine High School is among the scores of Leap Year Day babies who technically only get to celebrate their day of birth every four years.

Being born on Feb. 29 does has its advantages, however.

“It’s fun. People make jokes about me having some sort of princess party for my birthday and think it’s funny that I’ll be able to drive soon even though I’ll only be 4, so I’ve kind of embraced it,” said Lilly, whose mom actually did throw her a tongue-in-cheek princess party for her “third birthday” on Leap Day four years ago when she turned 12.

She even recreated the princess castle cake Lilly had at her third birthday party.

This year, the teen opted for a low-key Sweet 16 celebration with friends, but her mom couldn’t resist ordering a custom sign for their front yard wishing her daughter a “happy fourth birth date,” complete with a collection of leaping frogs to commemorate Leap Day.

White the Maddens don’t know anyone else with a Feb. 29 birthday, dozens of people responded to a Daily Reporter social media post asking about the unique birth date.

Back when she was pregnant with her daughter, Lilly’s mom, Jenny, remembers hoping for a Leap Day baby even though she wasn’t due until March.

“Back then they wouldn’t let you go early,” recalled Jenny, although nature took its course and her daughter arrived on Leap Day after all.

“I like it because it’s different. It’s unique,” she said.

Having a unique birth date does come with occasional hiccups, however.

“A lot of times in school the teacher would do birthday announcements and Lilly would get left off because Feb. 29 doesn’t always automatically pull up when you don’t have Leap Day on the calendar,” she said.

According to experts, Leap Day plays a much bigger purpose than simply offering up a unique birth date every four years.

David Minton, an associate professor of planetary sciences at Purdue University, recently released a video explaining the science behind Leap Years and their timing with Earth’s rotation around the sun.

According to Minton, observing Leap Day every four years on Feb. 29 keeps the current Gregorian calendar properly synchronized with the seasons.

The Julian calendar created by Julius Caesar added a Leap Day every four years, but Minton says that was not quite right and the calendar would drift over centuries.

The Gregorian calendar adds in some extra offsets to keep the seasons in synch.

Now every year divisible by four becomes a Leap Year, except for end-of-century years, which must be divisible by 400 in order to be a Leap Year. For example, a Leap Year was observed in the year 2000 but not in 1900.

According to a press release shared by Purdue, Minton says it’s fascinating how the movement of planets influences our day-to-day lives.

Society is organized around timekeeping, he said, which is tied to the movement of the planets.

Minton says the orbits of the solar systems are changing over time, and that the length of the day has grown longer over Earth’s geologic history.

Eventually there will be no need for Leap Years, he said, but not for another two or three million years.

In the meantime, Leap Day babies like Lilly will continue to embrace the birth date that makes them so unique.

“I technically won’t have my next birthday until I’m 20, and I’ll only be 20 when I’m 80, so it’s pretty funny to think about,” she said.